We recently used a great online tool  for planning a bike trip. We went from the center of town to the Obersee using only bike paths. My husband downloaded it as an app on his mobile phone and guided us there with no problems. There are several language options to chose from including English and German.

PollyEster also has the following recommendations

The ADFC has just published a new map about bycicle tours and ideal routes for cyclists around Bielefeld funded by the state of North rhine Westfalia. It is  available at the Tourist information (tram stop Rathaus) or at the ADFC office on Stapenhorststrasse. If you want to email them you can do so in English, German, French or Italian. Alternatively, a multi-language tool is available here: